This invention relates in general to articles of composite materials suitable for imprinting with sublimation dyes, and to a method of manufacturing such composite articles.
The manufacture of structural elements and other articles from composite materials, with high strength fibers embedded in a polymer matrix, is known in the art. Such composite materials have excellent strength to weight characteristics and wide application.
Known processes for the manufacture of such composite articles generally include forming a series of layers or plies, where each ply may be the same or different, and where the fibers in each ply may be wrapped with different orientations or braiding patterns to meet the requirements of a particular structure. The processes employed and the apparatus for practicing these processes are known to those skilled in the art. They include a pultrusion process and a resin transfer molding process. Fiber materials which have been employed in the art include aramid, glass, carbon, or graphite, as well as materials such as ceramics and boron. The polymer matrix material typically is a thermoset resin such as polyester or epoxy resin. Alternatively, a variety of thermoplastic resins such as nylon, polypropylene, polycarbonate and the like have been used.
Sublimation-printing is a technique to imprint indicia in the form of designs, logos, characters, etc. into an article. Generally, a sublimation dye is encapsulated by an inert carrier that releases the dye into the surface of the article upon application of an external force. The encapsulated dye is contacted with the article and an external force, such as heat and/or pressure, is applied to rupture the carrier, causing the dye to migrate directly into the surface of the article.
Many manufactured articles require labeling on an external surface for environmental, aesthetic, identification or safety purposes. Quite frequently, the surface of the article does not lend itself to imprinting with indicia that are visually distinct and highly perceptible. For example, the composite can have an optically dark surface, due to coloration of the constituent resins and fiber, i.e., the optical quality is inherent. Therefore, a surface coating of an optically light color is desired before imprinting indicia by sublimation. Otherwise, indicia are visually indistinct, or of low distinctiveness, from the surface of the composite.
Coatings previously used in making the composite surface optically light include pigmented paints and the like. After coating the composite surface with such an optically-light material, a sublimation dye is transferred to the coated surface of the composite, leaving the image imprinted into the coated surface. Consequently, the current state of the art for the preparation of composite articles having an outermost surface which provides an optically-light color for application of visually-distinct sublimation print requires at least three steps. These steps include forming the article, coating the surface of the article with an optically-light surface ready for application of visually-distinct sublimation print, and sublimation printing.
The term "into", as used herein, means that the sublimation dye penetrates and/or coats the outer surface of the article.
Accordingly, an object of this invention is to provide a method for forming a composite article having a surface that is ready for visually-distinct sublimation print.
A further object of this invention is to provide a composite article that has a surface ready for visually-distinct sublimation print.
Other general and specific objects of the invention will in part be obvious and will in part appear hereinafter.